Fusible resins crosslinkable with

The high-molecular-weight products formed by the condensation of phenols with carbonyl compounds (especially with formaldehyde) are known as phenolic resins. They are mixtures of structurally nonuniform compounds that are initially soluble and fusible but which can become crosslinked (cured) by subsequent reactions. One distinguishes between acid- and base-catalyzed condensations, since they lead to different end products the properties of the condensation polymer are also affected by the mole ratio of phenol to formaldehyde. 

Although the majority of flame-resistant fibres are produced from fully aromatic and/or heterocyclic polymers, an alternative approach, based on utilization of crosslinked polymers, is also feasible. Phenol-formaldehyde fibres were produced by a process involving spinning of a fusible novolac resin followed by crosslinking of the precursor fibre. A recently developed nonflammable fibre with a low smoke-evolution is based on a copolymer of acrylic acid and acrylamide the carboxylic groups are crosslinked by zinc ions. ... 

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